Generally speaking, a small-sized snowmobile is constructed with an engine mounted in the front portion of the frame of the chassis and a seat attached to the upper side of the rear portion of the frame. The frame is customarily press-molded of a steel or aluminum plate with steps integrally formed that comprise side plates extending downward and foot plates projecting outwardly sidewise of the chassis from the lower ends of the side plates while also extending in the longitudinal direction. If the rear ends of these steps are to be left free and unsupported, the shaping of the rear end edges becomes diificult, and the strength of the steps is insufficient. According to the prior art, therefore, triangular reinforcement plates are attached to the rear end edges of the side plates and the foot plates of the steps to reinforce the rear end portions of the steps. However, although this prior art technique can provide reinforcement for the rear end portions of the steps, the angular portions still remain at the rear end portion of the steps, and thus the shaping remains difficult.
It is an object of this invention to provide means to reinforce the steps at their rear ends, while facilitating the shaping of the steps themselves.